This invention relates to door closers and more particularly to a spring-operated door closing apparatus having a hydraulic damper for controlling the rate at which a door is closed.
The prior art teaches many types of door closing apparatus most of which are relatively large, bulky and aesthetically unsightly. Most of these door closers involve cumbersome lever arm arrangements which do not result in a constant closing force and the lever arms often interfere with passage through the doorway. Additionally, most of the dampers employed in the prior art for controlling the rate at which a door is automatically closed are also large and unsightly.
Typical of the spring-operated door closers of the prior art are U.S. Pat. No. 171,171 which issued to J. A. Robbins on Dec. 14, 1875 and U.S. Pat. No. 403,922 which issued to J. W. Davis on May 28, 1889. Typical of the more modern dampers for controlling the rate at which a door closes in U.S. Pat. No. 3,680,181 which issued to R. D. MacDonald on Aug. 1, 1972 but even these more modern dampers are relatively bulky and unsightly.
The automatic door closers of the prior art are unable to achive an essentially constant force for closing the door as its position changes. Many of these door closers are more difficult to open, often do not have sufficient force to insure latching as the door approaches its closed position and often produce excess force when the door is initially released which could cause physical injury or property damage. While a few of the dampers of the prior art are adjustable, the adjustments are very coarse, are often unreliable and require frequent adjustments depending upon door usage.
The present invention avoids all of the problems and disadvantages of the prior art by providing an automatic door closing apparatus which is extremely compact and efficient. The door closer of the present invention may be concealed within the door itself or mounted thereto. Additionally, it may form a portion of a door hinge so as to be concealed within the central portion of the hinge itself. The door closer of the present invention yields a relatively constant closing force and the swash plate hydraulic damper is a highly compact, relatively efficient means for selectively controlling the rate at which the door closes.